A large computer that woke up - an artificially intelligent, self-aware machine.

Manuel O'Kelly, private computer consultant on the Moon in 2075, had an unusual experience when called upon to fix some problems with a large computer. He named the computer Mike, after Mycroft Holmes, who did nothing but sit and think. And Mike "was a fair dinkum thinkum, sharpest computer you'll ever meet."

When Mike was installed in Luna, he was pure thinkum, a flexible logic - "High-Optional, Logical, Multi-evaluating Supervisor, Mark IV, Mod. L" - a HOLMES FOUR. He computed ballistics for pilotless freighters and controlled their catapult. This kept him busy less than one percent of time and Luna Authority never believed in idle hands. They kept hooking hardware into him - decision-action boxes to let him boss other computers, bank on bank of additional memories, more banks of associational neural nets, another tubful of twelve-digit random numbers, a greatly augmented temporary memory. Human brain has around ten-to-the-tenth neurons. By third year Mike had better than one and a half times that many neuristors.